The encampment, on the sidewalk in front of the Federal Reserve Bank at 101 Market St., was the original Occupy protest site established in early October, but police had cleared it several times. The camp sprang up again Thursday after police removed campers from Justin Herman Plaza a block away.

Beginning Saturday morning, police issued hourly warnings to the protesters that they were illegally lodging on the sidewalk and were subject to arrest. At 4 a.m. Sunday, officers ordered the protesters to leave, said San Francisco Police Officer Albie Esparza.

As officers moved in, protesters spat on several officers and shoved one, Esparza said. No demonstrators were injured, he said.

Nick Shaw, 32, of San Francisco said police kicked him and struck him with batons when he tried to retrieve his duffel bag during the sweep.

"They told me I had three seconds to get off the sidewalk, and I told them I have a right to be here - I'm a nonviolent protester," Shaw said, adding that police confiscated his bag. "Everything was in that bag - my medication, my birth certificate, my coat. Good thing I'm from Cleveland, or I would have froze to death."

By Sunday afternoon most of the protesters had been released from jail, and many had returned to the sidewalk with sleeping bags, protest signs and food. Several police officers stood in front of the bank, and Esparza said they would clear anyone who tried to sleep overnight.

"I'm undeterred," said protester James Cartmill, 40, of San Francisco. "Protesting, redressing our grievances, is the right thing for American patriots to do. People shouldn't be arrested for that."